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Java: Using AWT button to disconnect from chat server

I am programming a simple multi-threaded client/server chat system. Project requirements specify: "Connection only happens when the connect button is clicked. The disconnect button should disconnect the connection. A user should be able to connect, disconnect, re-connect at will." Basically, I have the connect button hooked-up and running. However, when I attempt to disconnect I get stuck in an infinite loop where the client side (on command line) infinitely prints "Sock closed", while the server side infinitely prints "Message read: null". This has lead me to look into all of my for(;;) loops to somehow close the connections within them, however I cannot figure out how to close the connection within those loops. Please help, this is my first socket programming project and I am super stumped on this one! Thanks all.
Client:
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import java.util.ArrayList;
public class ClientFrame extends Frame{
public ClientFrame(){
setSize(500,500);
setTitle("Chat Client");
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent We){
System.exit(0);
}
});
add(new ClientPanel(), BorderLayout.CENTER);
setVisible(true);
}
public static void main(String[] args){
new ClientFrame();
}
} // end ClientFrame
class ClientPanel extends Panel implements ActionListener, Runnable{
TextField tf;
TextArea ta;
List list;
Button connect, disconnect;
Socket socketToServer;
PrintWriter pw;
BufferedReader br;
Thread t;
String userName;
public ClientPanel(){
setLayout(new BorderLayout());
tf = new TextField();
ta = new TextArea();
list = new List();
connect = new Button("Connect");
disconnect = new Button("Disconnect");
Panel bPanel = new Panel();
bPanel.add(connect);
disconnect.setEnabled(false);
bPanel.add(disconnect);
tf.addActionListener(this);
add(tf, BorderLayout.NORTH);
add(ta, BorderLayout.CENTER);
add(list, BorderLayout.EAST);
add(bPanel, BorderLayout.SOUTH);
connect.addActionListener(this);
disconnect.addActionListener(this);
} // end ClientPanel constructor
public void actionPerformed(ActionEvent ae){
if (ae.getSource() == tf){
String temp = tf.getText();
pw.println(userName+": "+temp);
tf.setText("");
} else if (ae.getSource() == connect){
if(tf.getText() == null || tf.getText().equals("")){
ta.append("Must enter a name to connect\n");
}else {
userName = tf.getText();
connect.setEnabled(false);
disconnect.setEnabled(true);
tf.setText("");
try{
socketToServer = new Socket("127.0.0.1", 3000);
pw = new PrintWriter(new OutputStreamWriter
(socketToServer.getOutputStream()), true);
br = new BufferedReader(new InputStreamReader
(socketToServer.getInputStream()));
}catch(UnknownHostException uhe){
System.out.println(uhe.getMessage());
}catch(IOException ioe){
System.out.println(ioe.getMessage());
}
}
t = new Thread(this);
t.start();
pw.println(userName);
pw.println(userName +" has entered the chat.");
}else if (ae.getSource()== disconnect){
try{
t.interrupt();
socketToServer.close();
}catch(IOException ioe){
System.out.println(ioe.getMessage());
}
}
} // end actionPerformed
public void run(){
for(;;){
try{
String temp = br.readLine();
ta.append(temp + "\n");
}catch(IOException ioe){
System.out.println(ioe.getMessage());
}
}
} // end run
} // end ClientPanel
Server:
import java.io.*;
import java.net.*;
import java.util.ArrayList;
import java.awt.*;
public class ThreadedServerWithPresence{
public static void main(String[] args){
ArrayList<ThreadedHandlerWithPresence> handlers;
try{
handlers = new ArrayList<ThreadedHandlerWithPresence>();
ServerSocket s = new ServerSocket(3000);
for(;;){
Socket incoming = s.accept( );
new ThreadedHandlerWithPresence(incoming,
handlers).start();
}
}catch (Exception e){
System.out.println(e);
}
}
}
class ThreadedHandlerWithPresence extends Thread{
Socket incoming;
ArrayList<ThreadedHandlerWithPresence> handlers;
PrintWriter pw;
BufferedReader br;
String userName;
public ThreadedHandlerWithPresence(Socket i,
ArrayList<ThreadedHandlerWithPresence> handlers){
incoming = i;
this.handlers = handlers;
handlers.add(this);
}
public void setUserName(String userName){
this.userName = userName;
}
public String getUserName(){
return userName;
}
public void run(){
try{
br = new BufferedReader(new InputStreamReader
(incoming.getInputStream()));
pw = new PrintWriter(new OutputStreamWriter
(incoming.getOutputStream()),true);
String firstLine = br.readLine();
setUserName(firstLine);
for(;;){
String temp = br.readLine();
System.out.println("Message read: " + temp);
for(int i = 0; i < handlers.size(); i++){
handlers.get(i).pw.println(temp);
}
}
}catch (Exception e){
System.out.println(e);
}finally{
handlers.remove(this);
}
}
}

Client
Your run method does not handle interruptions so the for loop does not end and it continues trying to receive messages.
You must add an action that can be interrupted and throws InterruptedException, Thread.sleep would be a good candidate in this case, also reducing CPU usage (You do not need to check for new messages every single moment).
try {
for (; ; ) {
try {
String temp = br.readLine();
ta.append(temp + "\n");
} catch (IOException ioe) {
System.out.println(ioe.getMessage());
}
Thread.sleep(10);
}
} catch (InterruptedException e) {
System.out.println("Disconnected.");
}
Server
When br.readLine() returns null, that indicates the connection is closed by the client and you should stop receiving messages.
String temp = br.readLine();
if(temp == null)
break;

How do you know how to limit how many client that could enter your basic group chat app server? (Maximum 10)

so here is my code :
Server.java
import java.io.*;
import java.net.*;
import java.util.*;
class Server implements Runnable{
Socket connectionSocket;
public static Vector clients=new Vector();
public Server(Socket s){
try{
System.out.println("Client Got Connected " );
connectionSocket=s;
}catch(Exception e){e.printStackTrace();}
}
public void run(){
try{
BufferedReader reader =
new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
BufferedWriter writer=
new BufferedWriter(new OutputStreamWriter(connectionSocket.getOutputStream()));
clients.add(writer);
while(true){
String data1 = reader.readLine().trim();
System.out.println("Received : "+data1);
for (int i=0;i<clients.size();i++){
try{
BufferedWriter bw= (BufferedWriter)clients.get(i);
bw.write(data1);
bw.write("\r\n");
bw.flush();
}catch(Exception e){e.printStackTrace();}
}
}
}catch(Exception e){e.printStackTrace();}
}
public static void main(String argv[]) throws Exception{
System.out.println("Threaded Chat Server is Running " );
ServerSocket mysocket = new ServerSocket(5555);
while(true){
Socket sock = mysocket.accept();
Server server=new Server(sock);
Thread serverThread=new Thread(server);
serverThread.start();
}
}
}
mychat.java
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
public class mychat implements Runnable
{
public JTextField tx;
public JTextArea ta;
public String login="Imed";
BufferedWriter writer;
BufferedReader reader;
public mychat(String l)
{
login=l;
ClientName z = new ClientName();
JFrame f=new JFrame(z.getName()+"'s Chat");
f.setSize(400,400);
JPanel p1=new JPanel();
p1.setLayout(new BorderLayout());
JPanel p2=new JPanel();
p2.setLayout(new BorderLayout());
tx=new JTextField();
p1.add(tx, BorderLayout.CENTER);
JButton b1=new JButton("Send");
p1.add(b1, BorderLayout.EAST);
ta=new JTextArea();
p2.add(ta, BorderLayout.CENTER);
p2.add(p1, BorderLayout.SOUTH);
f.setContentPane(p2);
try
{
Socket socketClient= new Socket("localhost",5555);
writer= new BufferedWriter(new OutputStreamWriter(socketClient.getOutputStream()));
reader =new BufferedReader(new InputStreamReader(socketClient.getInputStream()));
}
catch(Exception e){e.printStackTrace();}
b1.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ev)
{
String s=login+" : "+tx.getText();
tx.setText("");
try
{
writer.write(s);
writer.write("\r\n");
writer.flush();
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
);
f.setVisible(true);
}
public void run()
{
try
{
String serverMsg="";
while((serverMsg = reader.readLine()) != null)
{
System.out.println("from server: " + serverMsg);
ta.append(serverMsg+"\n");
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
startclient.java
public class startclient
{
public static void main(String [] args)
{
try
{
ClientName n = new ClientName();
mychat c=new mychat(n.getName());
Thread t1=new Thread(c);
t1.start();
}
catch(Exception e){e.printStackTrace();}
}
}
And last ClientName.java
import java.util.*;
public class ClientName
{
String name;
public String getName()
{
Scanner sc = new Scanner(System.in);
System.out.print ("Enter your name : ");
name = sc.nextLine();
return name;
}
}
So basically, i want to limit how many client that could join my server(which maximum is 10 client). And if there is another client that want to join the server after it is full, that client will be rejected so it cannot joined.
I think that's it, though if there are any other improvement in other areas at my code it will also be appreciated. Sorry for my bad english
*Oh and sorry since I forget to include it, but somehow when I start the client, it ask the name twice

You can fix main method in your server and add sayGoodBye() as follows:
private static final int CONNECTION_LIMIT = 10;
public static void main(String argv[]) throws Exception {
System.out.println("Threaded Chat Server is Running ");
ServerSocket mysocket = new ServerSocket(5555);
int socketCount = 0;
while (true) {
Socket sock = mysocket.accept();
Server server = new Server(sock);
if (socketCount++ < CONNECTION_LIMIT) {
Thread serverThread = new Thread(server);
serverThread.start();
} else {
// without starting a thread and notifying only new client
server.sayGoodbye();
}
}
}
public void sayGoodbye() throws IOException {
try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(connectionSocket.getOutputStream()))) {
writer.write("Sorry, new client connections are not accepted, bye for now");
} catch (Exception e) {
e.printStackTrace();
}
connectionSocket.close();
}

How to fix error: constructor Server in class Server cannot be applied to given types

Here is my code:
Server.java
import java.io.*;
import java.net.*;
import java.util.*;
class Server implements Runnable{
static int socketCount = 0;
Socket connectionSocket;
public static Vector clients=new Vector();
public Server(Socket s){
try{
System.out.println("Client Got Connected " );
connectionSocket=s;
}catch(Exception e){e.printStackTrace();}
}
public void run(){
try{
BufferedReader reader =
new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
BufferedWriter writer=
new BufferedWriter(new OutputStreamWriter(connectionSocket.getOutputStream()));
clients.add(writer);
while(true){
String data1 = reader.readLine().trim();
System.out.println("Received : "+data1);
for (int i=0;i<clients.size();i++){
try{
BufferedWriter bw= (BufferedWriter)clients.get(i);
bw.write(data1);
bw.write("\r\n");
bw.flush();
}catch(Exception e){e.printStackTrace();}
}
}
}catch(Exception e){e.printStackTrace();}
}
private static final int CONNECTION_LIMIT = 10;
public static void main(String argv[]) throws Exception {
System.out.println("Threaded Chat Server is Running ");
ServerSocket mysocket = new ServerSocket(5555);
while (true) {
Socket sock = mysocket.accept();
Server server = new Server(sock);
if (socketCount++ < CONNECTION_LIMIT) {
Thread serverThread = new Thread(server);
serverThread.start();
} else {
// without starting a thread and notifying only new client
socketCount--;
server.sayGoodbye();
}
}
}
public void sayGoodbye() throws IOException
{
try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(connectionSocket.getOutputStream())))
{
writer.write("Sorry, a new client connections are exceeding the server limit thus it will not be accepted");
} catch (Exception e)
{
e.printStackTrace();
}
connectionSocket.close();
}
public int getSocket()
{
return socketCount;
}
}
mychat.java
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
public class mychat implements Runnable
{
public JTextField tx;
public JTextArea ta;
Server asd = new Server();
public String login="Imed";
BufferedWriter writer;
BufferedReader reader;
public mychat(String l)
{
login=l;
startclient z = new startclient();
JFrame f=new JFrame(z.getName()+"'s Chat");
f.setSize(400,400);
JPanel p1=new JPanel();
p1.setLayout(new BorderLayout());
JPanel p2=new JPanel();
p2.setLayout(new BorderLayout());
tx=new JTextField();
p1.add(tx, BorderLayout.CENTER);
JButton b1=new JButton("Send");
p1.add(b1, BorderLayout.EAST);
ta=new JTextArea();
p2.add(ta, BorderLayout.CENTER);
p2.add(p1, BorderLayout.SOUTH);
f.setContentPane(p2);
try
{
Socket socketClient= new Socket("localhost",5555);
writer= new BufferedWriter(new OutputStreamWriter(socketClient.getOutputStream()));
reader =new BufferedReader(new InputStreamReader(socketClient.getInputStream()));
}
catch(Exception e){e.printStackTrace();}
b1.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ev)
{
String s=login+" : "+tx.getText();
tx.setText("");
try
{
writer.write(s);
writer.write("\r\n");
writer.flush();
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
);
f.setDefaultCloseOperation (JFrame.DO_NOTHING_ON_CLOSE);
f.addWindowListener(new java.awt.event.WindowAdapter() {
#Override
public void windowClosing(java.awt.event.WindowEvent windowEvent) {
if (JOptionPane.showConfirmDialog(f,
"Are you sure you want to close this window?", "Close Window?",
JOptionPane.YES_NO_OPTION,
JOptionPane.QUESTION_MESSAGE) == JOptionPane.YES_OPTION){
asd.getSocket() = asd.getSocket() - 1;
System.exit(0);
}
}
});
f.setVisible(true);
}
public void run()
{
try
{
String serverMsg="";
while((serverMsg = reader.readLine()) != null)
{
System.out.println("from server: " + serverMsg);
ta.append(serverMsg+"\n");
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
startclient.java
import java.util.*;
public class startclient
{
static String name;
public static void main(String [] args)
{
try
{
Scanner sc = new Scanner(System.in);
System.out.print ("Enter your name : ");
name = sc.nextLine();
mychat c=new mychat(name);
Thread t1=new Thread(c);
t1.start();
}
catch(Exception e){e.printStackTrace();}
}
public String getName()
{
return name;
}
}
Every time I try to compile the mychat.java, I get this error message:
mychat.java:13: error: constructor Server in class Server cannot be applied to given types;
Server asd = new Server();
^
required: Socket
found: no arguments
reason: actual and formal argument lists differ in length
mychat.java:90: error: unexpected type
asd.getSocket() = asd.getSocket() - 1;
^
required: variable
found: value
2 errors
I want to limit how many clients can join the server, which kind of works, by adding a new integer called socketCount at Server.java and then increasing the count every time there are new clients joining and if the number of clients is exceeding the server limit, it will reject it.
But it seems that even though I already close the client, the socketCount value is still not decreasing and thus a new client could not enter even though I already giving it places.
Which is why I try to fix it by decreasing the socketCount value at mychat.java every time I close the program, but this error happens.
How can I resolve the error?

You can see the error log here:
mychat.java:13: error: constructor Server in class Server cannot be applied to given types;
Server asd = new Server();
That means you have to put the Socket whenever you create the Server instance.
Your constructor here:
public Server(Socket s){
try{
System.out.println("Client Got Connected " );
connectionSocket=s;
}catch(Exception e){e.printStackTrace();}
}
So, put the Socket to your instance and it should work fine.
Besides that, you should format your codes to be more readable. The class/methods should follow the Coding Convention. It will help you in the future.
Hope this help

java how to get a string to a server (jave.net/sockets)

I've been working on building a chat server to learn about threading and using sockets. I used head first java as a guide (and I'm still confused about a couple of things, which is why I have this question probably :D) and the code below is what I have.
If you read my code, you'll see that I have clients connect to the server by clicking on a "connect" button. When they do that, a new jframe pops up that asks for their preferred name for the chat session. When they input that, it's saved in a String in the client code. My question is, how do I get this name over to the server, and make it so that every time the client sends a message, their name is displayed before their message?
Thank you for the help!!!
(ALSO, if anyone knows a good link that can explain sockets and how socket/client interaction occurs through threads, that would be great!)
server code:
import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
public class GameServerOne {
ArrayList clientOutputStreams;
String clientName;
private class ClientThreadHandler implements Runnable {
BufferedReader clientIncomingReader;
Socket socket1;
public ClientThreadHandler(Socket clientSocket2) {
try {
socket1 = clientSocket2;
InputStreamReader clientInputReader = new InputStreamReader(socket1.getInputStream());
clientIncomingReader = new BufferedReader(clientInputReader);
} catch (Exception e) {
e.printStackTrace();
}
}
public void run() {
String message;
try {
while ((message = clientIncomingReader.readLine()) != null) {
tellEveryone(message);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
public void tellEveryone(String message) {
Iterator it = clientOutputStreams.iterator();
while(it.hasNext()) {
try {
PrintWriter writer = (PrintWriter) it.next();
writer.println(message);
writer.flush();
} catch (Exception e) {
e.printStackTrace();
}
}
}
public void setUpServer() {
clientOutputStreams = new ArrayList();
try {
ServerSocket gameSocket = new ServerSocket(5151);
//System.out.println("Server Connected");
while (true) {
Socket clientSocket = gameSocket.accept();
PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());
writer.println("User connected");
writer.flush();
clientOutputStreams.add(writer);
Thread t = new Thread(new ClientThreadHandler(clientSocket));
t.start();
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
public static void main(String[] args) {
new GameServerOne().setUpServer();
}
}
Client code:
import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class GameClientOne {
Socket gameSocket;
JFrame inputNameFrame;
JFrame clientFrame;
JTextArea chatArea;
JTextField messageInput;
BufferedReader gameChatReader;
PrintWriter gameChatWriter;
JTextField nameField;
boolean sessionNamePicked = false;
String userSessionName;
BufferedReader gameBufferedReader;
public GameClientOne () {
setUpGUI();
}
public void setUpGUI() {
clientFrame = new JFrame("Game Window");
JPanel mainPanel = new JPanel(new BorderLayout());
JPanel southPanel = new JPanel(new BorderLayout());
JPanel centerPanel = new JPanel(new BorderLayout());
chatArea = new JTextArea();
chatArea.setWrapStyleWord(true);
chatArea.setLineWrap(true);
chatArea.setEditable(false);
JScrollPane chatScroller = new JScrollPane(chatArea);
messageInput = new JTextField();
messageInput.addKeyListener(new MessageInputFieldListener());
JButton sendButton = new JButton("Send");
sendButton.addActionListener(new SendButtonListener());
JPanel westPanel = new JPanel(/*new GridLayout(20, 1)*/);
JPanel eastPanel = new JPanel();
JButton connectButton = new JButton("Connect");
connectButton.addActionListener(new ConnectButtonListener());
connectButton.setPreferredSize(new Dimension(100, 28));
JPanel northPanel = new JPanel(new FlowLayout());
JLabel northTitleLabel = new JLabel("Game Screen");
westPanel.add(connectButton);
chatScroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS) ;
chatScroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
northPanel.add(northTitleLabel);
centerPanel.add(BorderLayout.CENTER, chatScroller);
southPanel.add(BorderLayout.CENTER, messageInput);
southPanel.add(BorderLayout.EAST, sendButton);
mainPanel.add(BorderLayout.SOUTH, southPanel);
mainPanel.add(BorderLayout.CENTER, centerPanel);
mainPanel.add(BorderLayout.WEST, westPanel);
mainPanel.add(BorderLayout.EAST, eastPanel);
mainPanel.add(BorderLayout.NORTH, northPanel);
clientFrame.add(mainPanel);
clientFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
clientFrame.setSize(450, 600);
clientFrame.setVisible(true);
messageInput.requestFocusInWindow();
}
public void setUpInputNameFrame() {
inputNameFrame = new JFrame("Insert Name");
JPanel mainPanel = new JPanel(new BorderLayout());
nameField = new JTextField();
nameField.addKeyListener(new NameFieldListener());
JButton submitButton = new JButton("Submit");
submitButton.addActionListener(new SubmitButtonListener());
JLabel inputNameLabel = new JLabel("Please pick a name for the chat session");
JPanel northPanel = new JPanel(new FlowLayout());
JPanel southPanel = new JPanel(new BorderLayout());
northPanel.add(inputNameLabel);
southPanel.add(BorderLayout.CENTER, nameField);
southPanel.add(BorderLayout.EAST, submitButton);
mainPanel.add(BorderLayout.NORTH, northPanel);
mainPanel.add(BorderLayout.SOUTH, southPanel);
inputNameFrame.add(mainPanel);
inputNameFrame.setSize(300, 150);
inputNameFrame.setVisible(true);
nameField.requestFocusInWindow();
}
public void connectToGameServer() {
try {
gameSocket = new Socket("127.0.0.1", 5151);
InputStreamReader gameSocketReader = new InputStreamReader(gameSocket.getInputStream());
gameBufferedReader = new BufferedReader(gameSocketReader);
gameChatWriter = new PrintWriter(gameSocket.getOutputStream());
chatArea.append("Connected with name: " + userSessionName + "\n");
Thread incomingTextThread = new Thread(new IncomingTextReader());
incomingTextThread.start();
//System.out.println("Connected to Game");
} catch (Exception e) {
System.out.println("Could not connect to game...");
e.printStackTrace();
}
}
//ALL LISTENER CLASSES BELOW HERE
//main chat page listeners
private class ConnectButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
if (!sessionNamePicked) {
setUpInputNameFrame();
} else {
chatArea.append("You already connected!\n");
}
}
}
private class SendButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
if (!sessionNamePicked) {
chatArea.append("Please connect first\n");
messageInput.setText("");
messageInput.requestFocusInWindow();
} else {
try {
gameChatWriter.println(messageInput.getText());
gameChatWriter.flush();
} catch (Exception ex2) {
ex2.printStackTrace();
}
//chatArea.append(userSessionName + ": " + messageInput.getText() + "\n");
messageInput.setText("");
messageInput.requestFocusInWindow();
}
}
}
private class MessageInputFieldListener implements KeyListener {
public void keyPressed(KeyEvent e) {
}
public void keyTyped(KeyEvent e) {
}
public void keyReleased(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_ENTER) {
if (!sessionNamePicked) {
chatArea.append("Please connect first\n");
messageInput.setText("");
} else {
try {
gameChatWriter.println(messageInput.getText());
gameChatWriter.flush();
} catch (Exception ex2) {
ex2.printStackTrace();
}
//chatArea.append(userSessionName + ": " + messageInput.getText() + "\n");
messageInput.setText("");
}
}
}
}
//pick chat session name listeners: nameField/submitButton
private class NameFieldListener implements KeyListener {
public void keyPressed(KeyEvent e) {
}
public void keyTyped(KeyEvent e) {
}
public void keyReleased(KeyEvent e) {
if (!nameField.getText().isEmpty() && e.getKeyCode() == KeyEvent.VK_ENTER) {
userSessionName = nameField.getText();
sessionNamePicked = true;
connectToGameServer();
inputNameFrame.dispose();
messageInput.requestFocusInWindow();
}
}
}
private class SubmitButtonListener implements ActionListener {
public void actionPerformed (ActionEvent e) {
if (!nameField.getText().isEmpty()) {
userSessionName = nameField.getText();
sessionNamePicked = true;
connectToGameServer();
inputNameFrame.dispose();
messageInput.requestFocusInWindow();
}
}
}
//Runnable implementation for threads
private class IncomingTextReader implements Runnable {
public void run() {
String incomingMessage;
try {
while ((incomingMessage = gameBufferedReader.readLine()) != null) {
chatArea.append(incomingMessage + "\n");
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
GameClientOne gameClient = new GameClientOne();
}
}

If you want to send more than just a message as you are now, you are going to need a protocol to decide what to do with the string you receive, instead of just sending it to all the other clients.
For example, on the client side to send the client's name you might write NAME:(client's name), and then on the server you would split the string at the : and check if the first part is NAME, and if so set the clients name to the rest of the string. You should think about what other types of data you might want to send aswell and design a protocol that works for it.
Here's an example of how to do the above:
On the client you could add the line gameChatWriter.write("NAME:"+name) (create name first of course) imediatly after the connection is made. Then on the server, instead of calling tellEveryone(message) when the message is recieved create a method called processInput and call it, which might look like this:
private void processInput(String message){
String[] commands=message.split(':');
if(commands[0].equals("NAME")){
clientName=commands[1];
}
else{
tellEveryone(message);
}
}
Right now you only have one String clientName and you will obviously need more for the other clients you want to talk to so I would recommend making the thread handler into a seperate class which you would instantiate for each client and could hold things like that.
After you get this to work you could also create a seperate method to write other things that you want to send to either the client or server and a method to process input on the client side as well. Hope this helps.

Java - send a file over socket(chat client -> server -> another chat client)

So I'm working on a chat program and now I want to add a send file option.
I tried adding it and it worked but right after the file transfer finishes, both of the sockets close(the sockets of the two clients).
Here is an SSCCE for the Chat client:
public class SSCCEChatClient extends JFrame {
private JPanel contentPane;
private JTextField inputUsernameField;
private JTextArea textArea;
String serversock = "84.252.37.82";
String username;
Socket sock;
BufferedReader reader;
PrintWriter writer;
InputStreamReader streamreader;
public class IncomingReader implements Runnable{
public void run() {
String stream;
String[] data;
try {
while ((stream = reader.readLine()) != null) {
data = stream.split("`");
if(data[2].equals("receiveFile")&&(!data[3].equals(username))){
DataInputStream in = new DataInputStream(sock.getInputStream());
byte[] bytes = new byte[Integer.parseInt(data[1])];
in.read(bytes);
FileOutputStream fos = new FileOutputStream(System.getProperty("user.home") + "\\Desktop\\" + data[0]);
fos.write(bytes);
fos.close();
in.close();
textArea.append("Success!");
}else if(data[2].equals("server")){
textArea.append(data[0]);
}
}
}catch(Exception ex) {
}
}
}//Incoming Reader
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SSCCEChatClient frame = new SSCCEChatClient();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public SSCCEChatClient() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new BorderLayout(0, 0));
setContentPane(contentPane);
textArea = new JTextArea();
contentPane.add(textArea, BorderLayout.SOUTH);
JButton btnNewButton = new JButton("Send File");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
File transferFile = new File (System.getProperty("user.home") + "\\Desktop\\PNG\\Night.png");
byte [] bytearray = new byte [(int)transferFile.length()];
try {
BufferedInputStream bin = new BufferedInputStream(new FileInputStream(transferFile));
bin.read(bytearray,0,bytearray.length);
DataOutputStream os = new DataOutputStream(sock.getOutputStream());
writer.println(transferFile.getName() + "`" + transferFile.length() + "`receiveFile`" + username);
writer.flush();
os.write(bytearray,0,bytearray.length);
os.flush();
bin.close();
os.close();
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("File transfer complete");
}
});
contentPane.add(btnNewButton, BorderLayout.CENTER);
JButton btnNewButton_1 = new JButton("Connect");
btnNewButton_1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
username = inputUsernameField.getText();
sock = new Socket(serversock, 5000);
streamreader = new InputStreamReader(sock.getInputStream());
reader = new BufferedReader(streamreader);
writer = new PrintWriter(sock.getOutputStream());
Thread IncomingReader = new Thread(new IncomingReader());
IncomingReader.start();
writer.println(username + "``connect");
writer.flush();
} catch (Exception ex) {
textArea.append("\nCannot Connect!");
}
}
});
contentPane.add(btnNewButton_1, BorderLayout.WEST);
inputUsernameField = new JTextField();
contentPane.add(inputUsernameField, BorderLayout.NORTH);
inputUsernameField.setColumns(10);
}
}
and here is the Server side:
public class SSCCEServer {
static ArrayList<PrintWriter> clientOutputStreams;
static ArrayList<DataOutputStream> clientDataOutputStreams;
static ArrayList<String> onlineUsers = new ArrayList<>();
public class ClientHandler implements Runnable {
BufferedReader reader;
Socket sock;
PrintWriter client;
public ClientHandler(Socket clientSocket, PrintWriter user) {
// new inputStreamReader and then add it to a BufferedReader
client = user;
try {
sock = clientSocket;
System.out.println(clientSocket.getRemoteSocketAddress().toString() + " - ");
InputStreamReader isReader = new InputStreamReader(sock.getInputStream());
reader = new BufferedReader(isReader);
}
catch (Exception ex) {
System.out.println("error beginning StreamReader");
}
}
public void run() {
String message;
String[] data;
try {
while ((message = reader.readLine()) != null) {
data = message.split("`");
if(data[2].equals("receiveFile")){
DataInputStream in = new DataInputStream(sock.getInputStream());
byte[] bytes = new byte[Integer.parseInt(data[1])];
in.read(bytes);
tellEveryone(data[0] + "`" + data[1] + "`" + data[2] + "`" + data[3]);
for(DataOutputStream dos:clientDataOutputStreams){
try {
dos.write(bytes);
dos.close();
}
catch (Exception ex) {
System.out.println("error telling everyone");
}
}
tellEveryone("File transfer complete``server");
}else if(data[2].equals("connect")){
System.out.println(data[0] + "has connected.");
}else {
System.out.println("No Conditions were met.");
}
}
}
catch (Exception ex) {
System.out.println("lost a connection");
System.out.println(ex.getMessage().toString());
clientOutputStreams.remove(client);
}
}
}
public void tellEveryone(String message) {
// sends message to everyone connected to server
for(PrintWriter writer:clientOutputStreams){
try {
writer.println(message);
//pop("Sending: " + message);
writer.flush();
}
catch (Exception ex) {
System.out.println("error telling everyone");
}
}
}
public static void main(String[] args) {
new SSCCEServer().go();
}
public void go(){
clientOutputStreams = new ArrayList<PrintWriter>();
clientDataOutputStreams = new ArrayList<>();
try {
#SuppressWarnings("resource")
ServerSocket serverSock = new ServerSocket(5000);
while(true){
Socket clientSock = serverSock.accept();
PrintWriter writer = new PrintWriter(clientSock.getOutputStream());
clientOutputStreams.add(writer);
clientDataOutputStreams.add(new DataOutputStream(clientSock.getOutputStream()));
Thread listener = new Thread(new ClientHandler(clientSock, writer));
listener.start();
}
}
catch (Exception ex)
{
System.out.println("error making a connection");
}
}
}
Sorry if it's really long but this is the minimal amount I could bring it to. Also it's not the whole thing because it misses the send text method but that doesn't affect the SSCCE. I've demonstrated the send method with the method 'tellEveryone' from the server side.
Also, the "\PNG\Night.png" is just an example, you can make your own folder and file in order to run the SSCCE.
What can I do to fix the closing of the socket after the file is send?

close all Objects in finally block (try - catch - finally)
you have got issue with Concurency in Swing, but there are three ways
a) proper ways
wrap code to the Runnable#Thread (easiest), have to wrap any changes to the Swing GUI into invokeLater()
use SwingWorker (implemented in standard ways), where methods publish, process and done quite guarante that all events are done on EDT
b) shortcuts, works but not proper of ways
wrap Swing GUI code into invokeLater() directly

The socket closes when you close the output stream. If you want to keep the socket open, do not close the stream. For reference have a look at SocketOutputStream.java